Illuminated caliper instrument

ABSTRACT

An illuminated caliper device includes a caliper assembly having first and second caliper legs each having a pointed tip and a pivot end. A pivot support and first and second pivot elements pivotally connects the pivot ends of the first and second caliper legs to the pivot support. A battery housing attached to the pivot support contains a battery. First and second light emitting diodes are coupled by a switch mounted on the battery housing to first and second terminals of the battery and produced light that is directed to areas of the surface to be measured by pointed tips of the legs. The intensity and color of light emitted by the first light emitting diode are such as to sufficiently illuminate the surface under low ambient illumination conditions without disrupting acquired night vision of a user.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of prior filed co-pendingU.S. provisional application Serial No. 60/301,533 filed Jun. 27, 2001entitled “ILLUMINATED CALIPER INSTRUMENT” by Robert A. Mackin andJeffrey M. Mackin.

BACKGROUND OF THE INVENTION

[0002] The invention relates to calipers or caliper instruments (alsosometimes referred to as dividers) of the type utilized by persons whowork in dark environments, for example paramedics needing to makemeasurements on a medical chart plotted by a heart monitoring instrumentunder “field conditions”, navigators, aviators, and other persons whomust measure the distance between two points of a chart plotted by aninstrument, a map, or other document under very low ambient illuminationconditions. It is important that the “night vision” of such persons notbe temporarily disrupted by the presence of unnecessarily bright “white”light on the document (or other surface) to allow measurement of thedistance between two points on the document. A person whose eyes areopen for approximately 15 to 20 minutes under dark conditions or verylow ambient illumination conditions acquires what is known as “nightvision”, wherein the person's eyes become much more sensitive to lowlevels of ambient illumination. If the eyes of a person who has acquirednight vision are suddenly subjected to relatively bright light,especially white light, the person is subjected to what is referred toas “night blindness”, wherein the acquired night vision is lost. Theperson then must reacquire his/her night vision by remaining in no-lightor very low-light conditions for another 15 to 20 minutes, during whichhe or she may be unable to recognize critically important things oroccurrences in the low ambient light conditions in which the person isworking.

[0003] Although a need for solving this problem has existed for longtime, no practical means for solving the problem, such as a compact,reasonably inexpensive illuminated caliper instrument, has beenprovided.

[0004] U.S. Pat. No. 5,115,571, issued May 26, 1992, by present inventorRobert A. Mackin, discloses a caliper instrument including a gearmechanism wherein the upper ends of the caliper legs are interlocked bygear teeth so that the caliper legs of the symmetrically in oppositedirections about a bisection axis.

SUMMARY OF THE INVENTION

[0005] Accordingly, it is an object of the invention to provide acaliper instrument which provides adequate illumination to a personworking under night conditions for very low ambient illuminationconditions for utilization of a caliper instrument to measure ordelineate the distance between points on a document or object withoutimpairing the night vision of the person measuring coordinating thedistance between the points.

[0006] Briefly described, and in accordance with one embodiment thereof,the invention provides a caliper instrument including a light emittingdiode, a battery, and an on/off switch contained/installed in a hub ofthe illuminated caliper instrument from which its caliper legs extend.The light emitting diode is oriented to illuminate an area on thedocument including a pair of points the distance between which is to bemeasured or delineated the by needle points of the caliper instrument.In one described embodiment, two light emitting diodes, preferably redlight emitting diodes or green light emitting diodes, arecontained/installed in/on the hub of the caliper instrument. The opticalaxis of one of the light emitting diodes is oriented at a predeterminedangle relative to a bisection axis of the optical instrument, and theoptical axis of the other light emitting diode is oriented at anasymmetrically opposite angle relative to the bisection axis, so thatpoints of the document touched by the needle points of the caliperinstrument when its caliper legs are opened wide are equally andadequately illuminated. In one embodiment, the light emitting diodes aremounted directly on lower portions of the legs to direct the lightprecisely to areas of the document or object to be measured by theneedle points. In another embodiment, fiber optic elements extendbetween each light emitting diode and a corresponding fiber optic lensattached to a lower portion of a corresponding leg.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a front elevational view of one embodiment of theilluminated caliper instrument of the present invention, in an openconfiguration.

[0008]FIG. 2 is an elevational view of the caliper instrument of FIG. 1in a closed configuration with a protective cap installed.

[0009]FIG. 3 is a side elevational view of the illuminated caliperinstrument of FIG. 1.

[0010]FIG. 4 is a partial exploded elevational view of the upper portionof the illuminated caliper instrument of FIG. 1.

[0011]FIG. 5 is a top view of a battery housing of the illuminatedcaliper instrument of FIG. 1.

[0012]FIG. 6 is bottom view of the illuminated caliper instrument ofFIG. 1 with its caliper legs spread wide open.

[0013]FIG. 7 is a schematic diagram of the circuitry including thebattery, switch assembly and light emitting diodes in the illuminatedcaliper instrument of FIG. 1.

[0014]FIG. 8 is a front elevational view of another embodiment of theilluminated caliper instrument of the present invention in which thelight emitting diodes are attached to lower portions of the caliperlegs.

[0015]FIG. 9 is a front elevational view of one embodiment of theilluminated caliper instrument of the present invention in which fiberoptic bundles are coupled between the light emitting diodes andcorresponding fiber optic lens attached to lower portions of the caliperlegs.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Referring to FIG. 1, illuminated caliper instrument 1 includes ahub 100 from which a pair of caliper legs 4 and 5 downwardly extend. Apair of needles 6 and 7 extend downwardly from the lower ends of legs 4and 5, respectively. Legs 4 and 5 are attached to a gear mechanism 36(see the bottom view shown in FIG. 6) which can be essentially identicalto that disclosed in the above referenced U.S. Pat. No. 5,115,571, sothat when the caliper legs 4 and 5 are “opened” or “closed” as indicatedby arc 8, the movement of each leg 4 and 5 is symmetrically oppositewith reference to a bisection axis 9. (Alternatively, the upper ends oflegs 4 and 5 can be pivotally attached to hub 100 without use of gearmechanism 36.)

[0017] Hub 100 includes the above-mentioned gear mechanism 36, which isincludes two engaged gears attached to the upper ends of caliper legs 4and 5, which are pivotally connected to a gear housing 10, within gearhousing 10. An annular cap retaining ring 12 is rigidly attached to anddisposed around the periphery of the upper portion of gear housing 10.The plane of retaining ring 12 is perpendicular to bisection axis 9. AnO ring 11 is disposed in a groove (not shown), the plane of which isparallel to the plane of cap retaining ring 12.

[0018] Hub 100 includes a cylindrical battery housing 13 into which aswitch mechanism 16 having outer threads 30 is threaded. Switchmechanism 16 includes a suitable switch control element 17, which can bea rotary device or a depressible switch button or the like.

[0019] As shown in FIG. 2, when legs 4 and 5 are in a “closed”configuration, i.e., have been moved close to each other so that bothare parallel to bisection axis 9, then a protective cylindrical cap 20can be slid over O ring 11 and abutted against the lower edge of annularcap retaining ring 12. A suitable pocket clip 14 can be attached to thelower end of protective cap 20 as shown in FIG. 2, wherein referencenumeral 1A designates the illuminated caliper instrument 1 withprotective cap 20 in place. If desired, pocket clip 14 can instead beprovided at the upper end of protective cap 20 as indicated by dottedlines 14A.

[0020] Referring to FIGS. 1 and 3, a first light emitting diode 22 and asecond light emitting diode 23 are powered by the battery 32 (FIG. 5)retained in battery housing 13 when switch mechanism 16 is actuated orturned on. Battery 32 can be a suitable, readily available hearing aidtype of battery or button-type battery.

[0021] First light emitting diode 22 is installed at the bottom portionof gear housing 10 adjacent to the left side of legs 4 and 5 as shown inFIGS. 1 and 3, so that the optical axis of light emitting diode 22 isgenerally oriented in a direction indicated by arrow 25, so as toadequately illuminate a portion of a document or other surface (notshown) to be contacted by the tip of needle 6 when legs 4 and 5 arespread fairly far apart. Similarly, second light emitting diode 23 isinstalled on the right side of legs 4 and 5 as shown in FIG. 3, so thatthe optical axis of light emitting diode 23 is generally oriented in adirection indicated by arrow 26, so as to adequately illuminate aportion of the document or surface to be contacted by the tip of needle7 when legs 4 and 5 are spread fairly far apart.

[0022] Light emitting diodes 22 and 23 can be, for example, red lightemitting diodes or green light emitting diodes of recent high-intensitydesign. In recent years, low-power light emitting diodes of sufficientlyhigh intensity to illuminate a document for reading purposes have becomeavailable. Such light emitting diodes are available in both red andgreen colors, which are less likely to interfere with the night visionof a person such as a paramedic, navigator, aviator astronomer, or thelike who is working in darkness or in low ambient light conditions andis depending on his/her “night vision” to accomplish his/her work.

[0023] Therefore, when such person turns on light emitting diodes 22 and23 of illuminated caliper instrument 1 to measure the distance betweentwo points on the document, the intensity of the illumination producedon the document by light emitting diodes 22 and 23 does not appreciablyinterfere with the person's night vision because the light is directedto the document or surface rather than to the person's eyes. Thesignificantly reduces the chance of the person undergoing nightblindness.

[0024] Referring to FIGS. 4 and 5, the switch mechanism 16 hasperipheral threads 30 disposed on its lower portion. The externalthreads 30 mate with internal threads 34 of battery housing 13, soswitch assembly 16 can be threaded into battery housing 13 when battery32 is in place within battery housing 13.

[0025]FIG. 7 shows the schematic diagram of the light emitting diodes 22and 23, switch assembly 16, and battery 32 referred to above. Battery 32actually is composed of several button type batteries stacked in series.The (+) terminal of battery 32 is connected to one terminal of switchassembly 16, the other terminal of which is connected to the anodes oflight emitting diodes 22 and 23. The cathodes of light emitting diodes22 and 23 are connected to the negative terminal of battery 32.(Alternatively, light emitting diodes 22 and 23 could be connected inseries.)

[0026] In another embodiment, light emitting diodes 22 and 23 areattached directly to upper portions of caliper legs 4 and 5,respectively, so that the optical axes of the two light emitting diodeschange direction along with the longitudinal axes caliper legs 4 and 5,respectively, as they are moved in the directions indicated by arc 8.

[0027] In another embodiment 1B shown in FIG. 8, light emitting diodes22 and 23 are attached directly to lower ends of caliper legs 4 and 5,respectively, so that the optical axes of the two light emitting diodeschange direction along with the longitudinal axes of caliper legs 4 and5, respectively, as they are moved in the directions indicated by arc 8.The shorter distances between the between the light emitting diodes andthe document or object to be measured results in increased illuminationthereof. In this case, two pairs of electrical conductors 55 and 56extending along caliber legs and 5 and 4, respectively, couple lightemitting diodes 22 and 23, respectively, to switch mechanism 16 andbattery 32.

[0028] In another alternative embodiment 1C shown in FIG. 9, two pairsof fiber optic bundles 51 and 52 extend along caliper legs 5 and 4,respectively, to couple light emitting diodes 22 and 23 to fiber opticlenses 7 and 6 which are respectively attached to the lower ends ofcaliper legs 5 and 4. This arrangement directs the light precisely andwith increased intensity to smaller areas of the document or object tobe contacted and/or measured by the tips of the needles 6 and 7.

[0029] While the invention has been described with reference to severalparticular embodiments thereof, those skilled in the art will be able tomake the various modifications to the described embodiments of theinvention without departing from the true spirit and scope of theinvention. It is intended that all elements or steps which areinsubstantially different or perform substantially the same function insubstantially the same way to achieve the same result as what is claimedare within the scope of the invention.

[0030] For example, in some cases a single light emitting diode could beprovided, for example, between caliper legs 4 and 5, to illuminate thearea of the document or surface to be measured.

What is claimed is
 1. An illuminated caliper device, comprising: (a) acaliper assembly including i. first and second caliper legs each havinga pointed tip and a pivot end, ii. first and second pivot elementsattached to the pivot ends of the first and second caliper legs,respectively, the first and second pivot elements engaging each other tocause symmetrical opening and closing of the first and second caliperlegs, iii. a pivot support and first and second pivot elements pivotallyconnecting the pivot ends of the first and second caliper legs to thepivot support; and (b) a battery housing attached to the pivot supportfor containing a battery; (c) a first light emitting diode coupled by aswitch mounted in fixed relation to the battery housing to first andsecond terminals of the battery, the first light emitting diode havingan optical axis extending to an area of the surface containing at afirst point to be touched by a pointed tip of the first caliper leg. 2.An illuminated caliper device, comprising: (a) a caliper assemblyincluding i. first and second caliper legs each having a pointed tip anda pivot end, ii. first and second gear elements attached to the pivotends of the first and second caliper legs, respectively, the first andsecond gear elements engaging each other to cause symmetrical openingand closing of the first and second caliper legs, iii. a pivot supportand first and second pivot elements pivotally connecting the pivot endsof the first and second caliper legs to the pivot support; and (b) abattery housing attached to the pivot support for containing a battery;(c) a first light emitting diode coupled by a switch mounted in fixedrelation to the battery housing to first and second terminals of thebattery, the first light emitting diode having an optical axis extendingto an area of the surface containing at a first point to be measured bya pointed tip of the first caliper leg.
 3. The illuminated caliperinstrument of claim 2 including a second light emitting diode having anoptical axis extending to an area of the surface containing a secondpoint to be measured by a pointed tip of the second caliper leg.
 4. Theilluminated caliper instrument of claim 3 wherein the optical axes ofthe first and second light emitting diodes are oriented at symmetricallyopposite angles relative to a bisection angle of the illuminated caliperinstrument.
 5. The illuminated caliper instrument of claim 2 wherein thefirst light emitting diode emits red light.
 6. The illuminated caliperinstrument of claim 2 wherein the first light emitting diode emits greenlight.
 7. The illuminated caliper instrument of claim 2 wherein theintensity and color of light emitted by the first light emitting diodeare such as to sufficiently illuminate the surface and the first pointthereof to enable a person to visually position the pointed tip of thefirst caliper leg on or after the first point under low ambientillumination conditions without disrupting acquired night vision of theperson.
 8. The illuminated caliper instrument of claim 2 including arigid sheath snugly slidable over the caliper assembly.
 9. Theilluminated caliper instrument of claim 3 including a pocket clipattached to the sheath.
 10. An illuminated caliper device, comprising:(a) a caliper assembly including i. first and second caliper legs eachhaving a pointed tip and a pivot end, ii. first and second pivotelements attached to the pivot ends of the first and second caliperlegs, respectively, the first and second pivot elements engaging eachother to cause symmetrical opening and closing of the first and secondcaliper legs, iii. a pivot support and first and second pivot elementspivotally connecting the pivot ends of the first and second caliper legsto the pivot support; and (b) a battery housing attached to the pivotsupport for containing a battery; (c) a first light emitting diodecoupled by a switch mounted in fixed relation to the battery housing tofirst and second terminals of the battery, the first light emittingdiode being mounted in fixed relation to the first leg and having anoptical axis extending along the first leg to an area of the surfacecontaining a first point to be measured by a pointed tip of the firstcaliper leg, and a second light emitting diode coupled by the switch tothe first and second terminals of the battery, the second light emittingdiode being mounted in fixed relation to the second leg and having anoptical axis extending along the second leg to an area of the surfacecontaining a second point to be measured by a pointed tip of the secondcaliper leg.
 11. The illuminated caliper device of claim 10 whereinfirst light emitting diode is attached to a lower end portion of thefirst leg and the second light emitting diode is attached to a lower endportion of the second leg.
 12. An illuminated caliper device,comprising: (a) a caliper assembly including i. first and second caliperlegs each having a pointed tip and a pivot end, ii. first and secondpivot elements attached to the pivot ends of the first and secondcaliper legs, respectively, the first and second pivot elements engagingeach other to cause symmetrical opening and closing of the first andsecond caliper legs, iii. a pivot support and first and second pivotelements pivotally connecting the pivot ends of the first and secondcaliper legs to the pivot support; and (b) a battery housing attached tothe pivot support for containing a battery; (c) a first light emittingdiode coupled by a switch mounted in fixed relation to the batteryhousing to first and second terminals of the battery, the first lightemitting diode being coupled by a first fiber optic bundle to a firstfiber optic lens mounted in fixed relation to the first leg and havingan optical axis extending along the first leg to an area of the surfacecontaining a first point to be measured by a pointed tip of the firstcaliper leg, and a second light emitting diode coupled by the switch tothe first and second terminals of the battery, the second light emittingdiode being coupled by a second fiber optic bundle to a second fiberoptic lens mounted in fixed relation to the second leg and having anoptical axis extending along the second leg to an area of the surfacecontaining a second point to be measured by a pointed tip of the secondcaliper leg.
 13. The illuminated caliper device of claim 12 whereinfirst fiber optic lens is attached to a lower end portion of the firstleg and the second fiber optic lens is attached to a lower end portionof the second leg.